Online search engines generally rank web objects to present search results that are responsive to a search query. Search results for a query may be displayed in a particular order based on the ranking of the web objects. Search engines may rank the web objects based on various factors. For example, search engines may rank web pages based on information obtained from sources external to the web pages that reflect an inferred quality of the web page and on information about the content of the web pages that reflect the relevance of the web page with respect to a search query.